From ff4aa3bc98258a240b9bbab53fd8d2fb8184c485 Mon Sep 17 00:00:00 2001
From: Robert Marko <robimarko@gmail.com>
Date: Wed, 16 Aug 2023 18:45:39 +0200
Subject: [PATCH] firmware: qcom_scm: disable SDI if required

IPQ5018 has SDI (Secure Debug Image) enabled by TZ by default, and that
means that WDT being asserted or just trying to reboot will hang the board
in the debug mode and only pulling the power and repowering will help.
Some IPQ4019 boards like Google WiFI have it enabled as well.

Luckily, SDI can be disabled via an SCM call.

So, lets use the boolean DT property to identify boards that have SDI
enabled by default and use the SCM call to disable SDI during SCM probe.
It is important to disable it as soon as possible as we might have a WDT
assertion at any time which would then leave the board in debug mode,
thus disabling it during SCM removal is not enough.

Signed-off-by: Robert Marko <robimarko@gmail.com>
Reviewed-by: Guru Das Srinagesh <quic_gurus@quicinc.com>
Link: https://lore.kernel.org/r/20230816164641.3371878-2-robimarko@gmail.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
---
 drivers/firmware/qcom_scm.c | 30 ++++++++++++++++++++++++++++++
 drivers/firmware/qcom_scm.h |  1 +
 2 files changed, 31 insertions(+)

--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -407,6 +407,29 @@ int qcom_scm_set_remote_state(u32 state,
 }
 EXPORT_SYMBOL(qcom_scm_set_remote_state);
 
+static int qcom_scm_disable_sdi(void)
+{
+	int ret;
+	struct qcom_scm_desc desc = {
+		.svc = QCOM_SCM_SVC_BOOT,
+		.cmd = QCOM_SCM_BOOT_SDI_CONFIG,
+		.args[0] = 1, /* Disable watchdog debug */
+		.args[1] = 0, /* Disable SDI */
+		.arginfo = QCOM_SCM_ARGS(2),
+		.owner = ARM_SMCCC_OWNER_SIP,
+	};
+	struct qcom_scm_res res;
+
+	ret = qcom_scm_clk_enable();
+	if (ret)
+		return ret;
+	ret = qcom_scm_call(__scm->dev, &desc, &res);
+
+	qcom_scm_clk_disable();
+
+	return ret ? : res.result[0];
+}
+
 static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
 {
 	struct qcom_scm_desc desc = {
@@ -1411,6 +1434,13 @@ static int qcom_scm_probe(struct platfor
 
 	__get_convention();
 
+
+	/*
+	 * Disable SDI if indicated by DT that it is enabled by default.
+	 */
+	if (of_property_read_bool(pdev->dev.of_node, "qcom,sdi-enabled"))
+		qcom_scm_disable_sdi();
+
 	/*
 	 * If requested enable "download mode", from this point on warmboot
 	 * will cause the boot stages to enter download mode, unless
--- a/drivers/firmware/qcom_scm.h
+++ b/drivers/firmware/qcom_scm.h
@@ -77,6 +77,7 @@ extern int scm_legacy_call(struct device
 #define QCOM_SCM_SVC_BOOT		0x01
 #define QCOM_SCM_BOOT_SET_ADDR		0x01
 #define QCOM_SCM_BOOT_TERMINATE_PC	0x02
+#define QCOM_SCM_BOOT_SDI_CONFIG	0x09
 #define QCOM_SCM_BOOT_SET_DLOAD_MODE	0x10
 #define QCOM_SCM_BOOT_SET_ADDR_MC	0x11
 #define QCOM_SCM_BOOT_SET_REMOTE_STATE	0x0a
